In situ growth of TL-containing oxide superconducting films

摘要

In situ vapor phase growth of thallium containing superconductors is achieved by controlling thallium volatility. Thallium volatility is controlled by providing active oxygen at the surface of the growing material and by avoiding collisions of energetic species with the growing material. In the preferred embodiment, a thallium containing superconductor is grown by laser ablation of a target, and by provision of oxygen during growth. More specifically, a source of thallium, calcium, barium, copper and oxygen is created by laser ablation of a thallium rich target, generating an ablation plume that is directed onto a heated substrate through the oxygen, with the plume passing through oxygen having a pressure from 10.sup.-2 to ten torr. Epitaxial superconducting thin films of thallium, calcium, barium, copper and oxygen have been grown by this technique. Various superconducting phases may be engineered through use of this method.